Mechanical test methods of biomedical membranes such as used for otolaryngology.

Biomedical membranes, such as artificial tympanic membranes, are subject to noncontact internal air pressure. To estimate mechanical characteristics of such membranes, it is necessary to carry out the noncontact pressure test and membranous contact test, in addition to the usual monotonic tensile test, by using a rectangular specimen cut from the membranes. In this paper, these mechanical test methods and results on such biomedical membranes were studied. Some of the authors have already presented the mechanical test methods of cellophane membrane for hemodialysis under applied water pressure. Herein, we are concerned with the mechanical test methods of biomedical membranes such as tympanic membrane, in which gaseous pressure was applied.

Correlation between morbid adenoid and atelectatic ear.

We observed the nasopharynx of 30 patients with atelectatic ears (AE), and 10 with healthy ear drums and mouth breathing by CT scan, to examine the relation between adenoid and otitis media. The adenoids of those with healthy ear drums were of the large posterior type with free space in the pharyngeal fossa, while those with AE were of the large anterior type in 18 patients and of the pendulous projection type over the choana in the other 12. The anatomical location of the adenoids should be considered when one discusses the relation between the adenoid and otitis media. The "Toynbee phenomenon", in the pendulous projection type and in the large anterior type of adenoid, was considered to be one of the etiological factors in AE. To understand the etiology of otitis media, it seems important to investigate the reason why the anterior projection of the adenoids occurs.

Atelectatic ear and pathologic nasopharynx.

Pathologic relation between atelectatic ears and their nasopharynx were investigated in 50 patients with various degrees of atelectatic ears by transnasal fibrescope and C.T. And their morbid adenoids were compared with the adenoids of 20 patients with mouth breathing but free from ear problems. The process of drum bulging after catheterization, retraction after inflation, and inward movement during swallowing, proved that intratympanic pressure was influenced by nasopharyngeal pressure produced by swallowing, and that Eustachian tube itself was functioning to the pressure. Intratympanic negative pressure was proved by the movement of blue solution after the puncture of 5 atelectatic ear with effusion. And more dynamic negative pressure produced by swallowing was demonstrated in 5 other cases. The morbid adenoid with atelectatic eardrum was differentiated from the large posterior type of adenoid of the healthy eardrum, by the pendulous projection over the choana especially in swallowing. A dynamic vacuum caused by "Toynbee phenomenon" is discussed.

A morphological study of the vestibular sensory epithelia in the rabbit.

Surface preparations were made of the vestibular sensory end-organs of the rabbit. The total sensory cell counts and surface area measurements were made from the composite photographic reconstructions. The general topographical and cytoarchitectural arrangements were found to be similar to those previously described for guinea pigs, squirrel monkeys and humans. The sensory cell counts of the maculae are about 50% larger in the rabbit than in the guinea pig, while those of the cristae remained almost unchanged in both species of animals despite a large difference in both size and weight. The body size of the species does not seem to play a decisive role in determining the sensory cell population of the vestibular sensory end-organs. The growth of the maculae is compared with that of the cristae or vice versa seems to vary from one species to another, probably depending upon a physiological need of the species.

Epithelial changes in or of the middle ear mucoperiosteum. An experimental study.

In this study the time necessary for the increase of the secretory cells in the middle ear mucosa was investigated by EM and SEM and by histochemical observation of the secretory cells. The first experiment revealed that a minimum of six to seven days was required for the renewal of the columnar cytoarchitecture after the exposure to silver protein solution. In the next experiment 35 guinea pigs were subjected to tubal obstruction. Columnar metaplasia was found in one case sacrificed after the third month, and gland formations without myoepithelial cells and nerve endings were seen in those after the fourth month. In an additional experiment, since the frontal sinus of the dogs is simple and pneumatized, duct obstruction was performed. Slight epithelial change and accumulation of glue-like thick mucus, which was negative in culture, was found in all four cases after three months. In one of the two cases with obstruction for four months, typical exophthalmus in the pseduostratified epithelium with an increase in secretory cells or cuboidal epithelium with nonciliated cells was demonstrated.